1. Field of the Invention
The present invention relates generally to environment temperature sensing devices and more particularly to a micro-fabricated sensor with improved temperature sensitivity.
2. Description of the Prior Art
Micro-fabricated structures are finding a wider range of scientific and technological uses. One advantage of micro-fabricated devices is that many properties do not scale adversely with decreasing size. For example, as a structure decreases in size, the amount of energy required to raise the temperature scales linearly with volume. Thermal losses due to conduction, radiation, and convection vary with appropriate areas. Consequently, for fixed energy input, a larger temperature arises in a smaller structure. This property has a number of advantages for sensor applications. If temperature is the primary intensive thermodynamic variable used in the sensing process, the amount of energy required to modulate the temperature decreases with size.
Existing integrated temperature sensor devices for measuring changes in environment temperature typically employ resistors as temperature sensing elements. Several limitations have been noted, however, in resistor-based temperature sensing devices. For example, resistor-based integrated temperature sensing devices lack consistency in the temperature coefficient of resistance between batches of resistors. Furthermore, platinum and similar materials which are typically employed as the resistive element of such devices are expensive. Additionally, in resistor based integrated temperature devices, since the resistor is used both as a heater and as a thermometer, there is a direct change in the device's response when the applied power is modified.
Accordingly, there is a need in the art for an improved environment temperature sensing device. Specifically, there is a need for an integrated sensing device which overcomes the above listed limitations associated with resistor-based integrated sensing devices and which also provides improved temperature sensitivity.